For several decades, magnetic tape media and corresponding data storage devices known as tape drives have been used for storing digital data in non-volatile form, most commonly with the application of providing secondary or backup storage and retrieval. Initially the magnetic tapes were wound about large reels in similar manner as film for film projectors. In more recent years the magnetic tape has typically been housed in a cartridge or cassette, extending internally in the cartridge from a supply reel to a take-up reel. To allow interoperability between different tape media and tape drives, including those of different vendors, the mechanical dimensions and magnetic properties of the tape media, as well as the exact method according to which data is to be recorded on the tape media are typically governed by agreed industry standards.
With corporations shifting from single tape drives attached to single host computers to deploying large numbers of tape drives organised in tape libraries, the ability to use tape media interchangeably with a large number of tape drives has grown in importance. Adherence of tape media and tape drives used in a corporation to a common format, or to a set of compatible formats is therefore of great value. In another consequence, in order to early diagnose technical problems with a particular tape medium or tape drive it becomes increasingly important to be able to uniquely identify and track the tape usage history of each tape medium.
One known format of magnetic tape media for providing storage and retrieval of digital data is the Digital Data Storage (DDS) format, which has evolved from Digital Audio Tape (DAT) technology and developed through a number of versions. Each new version provided improvements over the preceding version, among those being one or more of enlarged capacity of the tape medium, higher speed of data recording and retrieval, improved reliability, and additional functionality for tape medium management.
The 6th version of the DDS format, which is known as DAT 160, provides the capability of the tape drive to uniquely identify a tape medium by recording a unique cartridge serial number on the tape medium. A further improvement introduced by the DAT 160 version is the capability to store an extended log of tape usage information on the tape medium, the extended log including twelve log sections in which tape usage information is recorded relating respectively to the last twelve data recording sessions. Tape usage information recorded in each log section includes usage and error statistics as well as an identification of the tape drive on which the tape medium was loaded during the respective session. Tape media complying with the DAT 160 version of the DDS format cannot be read or written to using tape drives produced according to an earlier version of the DDS format.
Among the versions of the DDS format in widespread use are the 3rd, 4th, and 5th version, known respectively as DDS-3, DDS-4, and DAT-72. These versions do not provide within their respective format specifications for the storage of a tape medium identifier that would allow uniquely identifying a tape medium.
The TapeWare backup application embeds a tape medium identifier within user data written to a tape medium. This identifier is lost when a different application is used to overwrite the user data on the tape medium.